1. Technical Field
The present invention relates in general to data processing systems and in particular to hard disk drives associated with data processing systems. Still more particularly, the present invention relates to a system, method and computer program product for recovery of formatting in repair of bad sectors in hard disk drives associated with a data processing system.
2. Description of the Related Art
Due to advances in electronic and magnetic technology, the capacity of hard drives at any given price point is doubling annually. While the advances in storage capacity that have been witnessed over the past decade have enabled a revolution in the type and quantity of data that can be stored, the correlative reductions in size and increases in the speed of moving parts have created a daunting array of obstacles to reliability.
The reliability of a hard drive is specified in terms of its mean time between failures (MTBF) and the unrecoverable error rate. Typical specifications for recent server-class drives are 1,000,000 hours MTBF and 1 unrecoverable error in 1015 bits read. However, increases in hard disk density make it harder to maintain reliability due to lower flying heights, greater sensitivity to media defects and smaller scale. Difficulties with error frequency have prompted the creation of error-correction techniques.
Some methods of error correction require manual intervention. Others, such as RAID (Redundant Array of Independent Disks) arrays (e.g., RAID-1 or RAID-5) are often used to further improve the reliability of storage systems by correcting a variety of errors through redundant storage. However, with high-capacity drives, a single level of redundancy is no longer sufficient to reduce the probability of data loss to a negligible level. Additionally and unfortunately, redundant storage of data or formatting increases both cost and storage capacity requirements.
It is also possible for a disk drive to occasionally return erroneous data on a read command because a previous write command has not written to the correct location on the recording medium or because the drive failed to record on the medium at all. This type of failure may be due to an intermittent hardware failure or a latent design defect. For example, the drive might write the data to the wrong LBA (Logical Block Address) due to a firmware bug, or it may write off track, or it may fail to write at all because a drop of lubricant (commonly referred to as ‘lube’) lifts the head off of the disk surface. It may also fail to write due to any power interruption during a write or format operation.
In data processing systems, failures to write carry the risk that formatting for data stored in a hard disk drive can become corrupted or damaged. As with the error correction methods for other problems in hard disks, prior art methods for recovering from corruption of formatting data involve the constant maintenance of redundant copies of the data or require that the user corrects the corruption of the formatting through replacement or manual repair.
The state of prior art methods results in several drawbacks. First, maintaining redundant copies of formatting data is not desirable, due to the associated increase in storage requirements. This concern about storage requirements becomes particularly important in embedded systems or other systems in which storage resources are limited. Similarly, prior art methods that require the user to correct the corruption of formatting data through replacement or manual repair involve time costs to the user or information technology personnel. The reduction of such costs is desired.